With the D-line, Keller introduces a unique combination consisting of an exceedingly robust
industrial pressure transducer and the popular I2C microcontroller interface. Pressure transmitters with this interface are commonly available only in consumer market housings made of plastic or ceramic, where merely the parameters for compensation are stored in an integrated memory. The D-line OEM transmitters however have an unprecedented embedded digital signal processing (DSP) core for the compensation and normalization of the output values.

Technology:
The Series 4 LD...9 LD is based on KELLER’s famous Chip-In-Oil (CIO) technology. The “L” stands for the laser welded stainless steel housing and could equally be representative for low- power (typ. 0,1 μA in idle/sleep mode) and low-voltage (Supply: 1,8...3,6 VDC). The housing is hermetically-sealed, oil-filled and builds a Faraday cage with feed-through capacitors around the entire electronics. The digital interface of the electronics with dual information of pressure and temperature is indicated by the “D”.

Interfaces:
The easiest way to couple an OEM pressure transmitter to a microcontroller based system is a digital I/O-compatible interface; no amplification, no analog to digital conversion, no calibration, no temperature coefficients. In short: no problems. I2C (Inter-Integrated Circuit) is designed for a direct connection between devices on a prin- ted circuit board. It is a BUS-system because it allows the connection of multiple transmitters (slaves) to the same communication lines, but it is not a fieldbus with the classic long distance inter-connectability. So the D-Line combines an industrial pressure interface for harsh environ- ment with an electrical interface for OEM applications.
The values are in 16 Bit unsigned integer format and the scaling is given by constants or by the memory content of the transmitter (two floating point values IEEE 754 for the pressure scaling).